The present invention relates to the presentation of map information on a display screen of a computing device, and more particularly, the present invention relates to a way to improve the presentation of map information on a display screen of a computing device when a user pans or zooms the displayed map.
There are various computing platforms that graphically display maps of geographic areas. For example, some in-vehicle navigation systems include a display screen upon which a map of a geographic area can be displayed graphically. In addition, by using appropriate software applications, maps can also be displayed on general purpose computing platforms, such as personal computers and personal digital assistants.
Some computing platforms and applications that display graphical maps include features that allow a user to interact with the map. Various types of user interaction may be supported. Among these types of user interaction is the ability to zoom in or out. When a user zooms in on a map, a sub-portion of the originally displayed map is selected. The user may operate a pointing device for this purpose. Then, a new map is graphically displayed. The new map corresponds to the geographic area of the selected sub-portion of the originally displayed map. The new map is at a larger scale than the originally displayed map so that new map fills the same area on the display screen of the computing device on which the originally displayed map had been shown.
When a user zooms out on a graphically displayed map, the new map is at a smaller scale than the previously displayed map. The new map corresponds to a geographic area that is larger than the geographic area that corresponds to the previously displayed map, such that the geographic area that corresponds to the previously displayed map is only a sub-portion of the geographic area that corresponds to the new map.
Panning is another type of user interaction that is supported by some computing platforms that graphically display maps. When a user “pans” a map, the displayed features are shifted without changing the magnification (i.e., the map scale stays the same). The map can be panned left, right, up, down, or diagonally.
Some computing platforms support smooth panning or zooming. With smooth panning, the graphically displayed map “slides” in an apparently smooth, continuous motion under the control of the user. Likewise, with smooth zooming, the map scale changes in a smooth continuous motion. On computing platforms that do not support smooth panning or zooming, the panning or zooming operations occur as abrupt, discrete jumps, i.e., the old map view is displayed, and then the new map view replaces it.
When a user interacts with a graphically displayed map by panning or zooming, there is a need for the user to be re-oriented to the graphically displayed map after the panning or zooming operation. The user may have known his/her relationship to the view shown prior to panning or zooming. In order to know his/her relationship to the view displayed after panning or zooming, the user needs to know the relationship between the prior displayed map and the new map. Knowing the relationship between the map views before and after panning and zooming can be difficult, especially on computing platforms that do not support smooth panning and zooming. Even on computing platforms that support smooth panning and zooming, it is sometimes difficult to know the relationship between the map views before and after panning and zooming.
Accordingly, there is a need for an improved way to represent map features when panning and zooming.